(a) Field of the Invention
The present invention relates to a bumper beam unit for a vehicle. More particularly, the present invention relates to a bumper beam unit for a vehicle that includes a plurality of space portions in a larger diameter pipe by press-forming a smaller diameter pipe that is inserted into the larger diameter pipe together with the larger diameter pipe.
(b) Description of the Related Art
In general, the bumper in the vehicle is a damping device mounted to predetermined parts of a front and a rear of the vehicle for absorbing a crash impact when the vehicle crashes into another vehicle or a fixed body for promoting occupant safety as well as minimizing vehicle body deformation.
FIG. 1 is an exploded perspective view of a conventional bumper of a vehicle.
Referring to FIG. 1, the bumper 100 is provided with a bumper beam 101 of which sides of a rear part thereof are fixed to sides of vehicle body side members 111 through stays 103, respectively, and that is disposed in a width direction of the vehicle, an energy absorber 107 disposed in front of the bumper beam 101 for absorbing an impact, and a bumper cover 109 for covering the bumper beam 101 and the energy absorber 107.
Because excellent strength and a weight reduction structure are becoming needed through development of production techniques, the bumper beam 101 has evolved from having an opened cross-sectional structure to a closed cross-sectional structure.
The bumper beam 101 of the closed cross-sectional structure has an equal cross-section throughout a length direction thereof due to a production process characteristic, and equal buckling has to be generated when it is impacted in a normal compression direction.
Therefore, a thickness or a cross-sectional shape of the bumper beam 101 has to be controlled so as to enhance crash absorption performance of the bumper beam 101.
However, when the thickness is increased or the cross-sectional shape of the bumper beam 101 is changed, the weight and the production cost of the bumper beam 101 are increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.